With science operations underway, the James Webb Space Telescope (JWST) newly reveals our Universe.
This comes ~6+ months after its initial launch.
Four reasons necessitated the long wait.
1.) Deployment: the observatory needed to unfold into its final configuration.
2.) Orbital insertion: it needed to arrive at its desired destination.
3.) Cooling: all of the components needed to reach operating temperature.
4.) Calibration and commissioning: each and every component requires it.
This includes both the optical system and each science instrument as well.
Arguably, the most difficult instrument to commission is MIRI: the mid-infrared instrument.
Unlike all others, passive cooling to ~40 K is insufficient for MIRI.
Probing the longest wavelengths, from 5-30 microns, demands operations below ~7 K.
JWST is pioneering a unique, closed-system cooler.
It’ll keep MIRI cryogenically cold indefinitely.
MIRI’s arsenic-doped silicon detectors encountered some novel issues.
These detectors saturate when viewing too-bright sources, producing afterimages.
The fix is thermal cycling: warming the instrument to ~20 K and cooling it back down.
MIRI’s spikes aren’t hexagonal, but display a unique “plus” shape.
Internal, short-wavelength reflections are the culprit; software is the remedy.
MIRI’s wavelength capabilities cover nine independent mid-infrared ranges.
Now fully commissioned, MIRI is revealing the mid-infrared cosmos.
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.